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May 13, 2009

Anxiety Triggered By Brain Chemical

by Sam Savage

A new study provides convincing evidence that points to a special chemical in the brain that may contribute to the reason some people have a genetic predisposition to anxiety, Reuters reported on Tuesday.

Such evidence could lead the way to new treatments.

In rats bred to be extremely anxious, very low levels of a brain chemical called fibroblast growth factor 2 or FGF2 could be detected, while low-key rats showed higher levels.

When the researchers added new toys to explore, an obstacle course and a bigger cage to improve the rats' living conditions, higher levels of this brain chemical could be detected and they were less anxious.

"The levels of this molecule increased in response to the experiences that the rats were exposed to. It also decreased their anxiety," Javier Perez of the University of Michigan, whose study appears in the Journal of Neuroscience, said in a telephone interview.

"It made them behave the same way as the rats that were laid back and had low anxiety to begin with," he elaborated.

Perez said that when the chemical was injected into the rats, this also made them less anxious.

In a previous study that involved people who suffered severe depression just before they died, the researchers found evidence that the gene that makes FGF2 was producing miniscule levels of the growth factor, which is primarily known for systematizing the brain during development and replenishing it after injury.

The brain chemical may be an indicator for genetic susceptibility to anxiety and depression, Perez supposes. However, it can also react to variances in the environment in a constructive way, potentially by preserving new brain cells.

Both calm and anxious rats produced equal number of new brain cells, but in high-anxiety rats these cells were less likely to sustain, findings reveal.

"This discovery may pave the way for new, more specific treatments for anxiety that will not be based on sedation, like currently prescribed drugs, but will instead fight the real cause of the disease," Dr. Pier Vincenzo Piazza of the University of Bordeaux in France, who had seen the study, said in a statement.

The study was financially supported partly by the Pritzker Neuropsychiatric Disorders Research Fund, which is seeking to patent the molecule, Perez informed. ---